A speaker kneels in a dark room beside someone they love, still a little angry, and kisses them anyway. The lips taste of blood, and glass is scattered across the floor. The poem never says what happened, and that gap is part of its power: we only see the aftermath of what looks like a fight or an injury.
Anger and tenderness sit side by side here. The speaker can't quite let go of the one, or hold back the other. Music drifts in through the window, classical guitars full of old passion, and it makes the moment feel both beautiful and out of reach. The speaker imagines the glass and "the soft parts of us" being gathered into a tragic love song, since that would at least make the pair seem less small. The mood is bruised, quiet, and weary, with a sad honesty about being too tangled up in each other to tidy anything.